Things Are Getting Hairy: Enterobacteria Bacteriophage vB_PcaM_CBB

Abstract

Enterobacteria phage vB_PcaM_CBB is a “jumbo” phage belonging to the family Myoviridae. It possesses highly atypical whisker-like structures along the length of its contractile tail. It has a broad host range with the capability of infecting species of the genera Erwinia, Pectobacterium, and Cronobacter. With a genome of 355,922 bp, excluding a predicted terminal repeat of 22,456 bp, phage CBB is the third largest phage sequenced to date. Its genome was predicted to encode 554 ORFs with 33 tRNAs. Based on prediction and proteome analysis of the virions, 29% of its predicted ORFs could be functionally assigned. Protein comparison shows that CBB shares between 33–38% of its proteins with Cronobacter phage GAP32, coliphages PBECO4 and 121Q as well as Klebsiella phage vB_KleM_Rak2. This work presents a detailed and comparative analysis of vB_PcaM_CBB of a highly atypical jumbo myoviridae phage, contributing to a better understanding of phage diversity and biology.

Jumbo Bacteriophages Are Represented Within an Increasing Diversity of Environmental Viruses Infecting the Emerging Phytopathogen, Dickeya solani

“…In their recent publication, Buttimer et al discussed the phylogenetic position of Y3 considering its low level of nucleotide identity to existing genomes (Buttimer et al, in press ). Two potential subfamilies within the “hairy Myoviridae ” have emerged; the Rak2-like phages, which includes the previously mentioned Pectobacterium phage CBB (Buttimer et al, 2017 ), and the as yet unnamed subfamily that encompasses the phage discussed here. This was established as it was found that Y3 had homologs including terminase, polymerase and helicase genes in several other phages reported or suspected to have the “hairy Myoviridae ” morphology.…”

“…It was also thought that the dimensions, at the time reported to be a head diameter of 150 nm and a tail length of 165 nm, were overstated. However, this morphology has since been directly reported in the Pseudomonas putida phage Lu11 (Adriaenssens et al, 2012b ), the Pectobacterium carotovorum phage CBB (Buttimer et al, 2017 ), and the Erwinia amylovora phage Y3 (Buttimer et al, in press ), and has been dubbed the “hairy Myoviridae ” morphology (Buttimer et al, 2017 ).…”

Xanthomonas citri jumbo phage XacN1 exhibits a wide host range and high complement of tRNA genes

“…Recently, a new group of jumbo phages has been recognized 5 . This group, named Rak2-like phages, is composed of phages with a genome longer than 300 kbp including Klebsiella phage vB_KleM-RaK2 6 , Escherichia phage PBECO 4 7 , Cronobacter phage vB_CsaM_GAP32 5 , Escherichia phage 121Q (accession number: NC_025447), Klebsiella phage K64-1 8 , Enterobacteria phage vB_PcaM_CBB 9 , and Serratia phage BF 10 . Rak2-like phages encode genes homologous to the “core genes” that are conserved among T4-related phages 6 , 11 .…”

“…Rak2-like phages encode genes homologous to the “core genes” that are conserved among T4-related phages 6 , 11 . However, given the level of sequence divergence, the lack of many of the core genes of T4-related phages, and a large number of genes that are shared within Rak2-like phages but not with T4-like phages, Rak2-like phages were proposed to be only distantly related to T4-like phages 9 .…”

Genomic characterization of three novel Basilisk-like phages infecting Bacillus anthracis

“…Although a plethora of functional yet truncated ARS paralogs and pseudogenes have been observed in bacterial genomes [ 43 ], to our knowledge, no such truncated ARSs have yet been reported in phage genomes. With the exception of tRNA genes, the overall presence of translation-associated genes in phages is rare [ 39 ] although select myoviruses and mimiviruses are known to encode complete ARS genes [ 43 , 44 ].…”